Ultimate Guide: Using a PIR Motion Sensor with Arduino for Motion Detection

Components Required:

Circuit Setup:

PIR Sensor Connections:

• VCC to 5V on Arduino
• GND to GND on Arduino
• OUT to Digital Pin 2 on Arduino

LED Connections:

• Anode (longer leg) to Digital Pin 13 via 330Ω Resistor
• Cathode (shorter leg) to GND

Adjusting the PIR Sensor:

Use the potentiometers to adjust:

• Sensitivity: Controls the detection range.
• Time Delay: Determines how long the output remains high after detecting motion.

Arduino Code:

int ledPin = 13;
int pirPin = 2;
int pirState = LOW;
int val = 0;

void setup() {
  pinMode(ledPin, OUTPUT);
  pinMode(pirPin, INPUT);
  Serial.begin(9600);
}

void loop() {
  val = digitalRead(pirPin);
  if (val == HIGH) {
    digitalWrite(ledPin, HIGH);
    if (pirState == LOW) {
      Serial.println("Motion detected!");
      pirState = HIGH;
    }
  } else {
    digitalWrite(ledPin, LOW);
    if (pirState == HIGH) {
      Serial.println("Motion ended!");
      pirState = LOW;
    }
  }
}
        

Operation:

Once uploaded, allow the PIR sensor to calibrate for 30 seconds. The LED will turn on when motion is detected and turn off after the delay time.

Adjust sensitivity and delay settings for different applications.